It is common practice to package beverages, such as beer and soft drinks, in metallic cans. The most prevalent type of metallic can today for beverage packaging is the two-piece aluminum can, comprising a drawn and ironed can body produced from a circular blank of aluminum and an aluminum end closure double seamed to a flange at the top of the can body. The end normally includes an easy-opening feature, such as a ring pull tab or a nondetachable tab opening structure.
Normally, due to the relatively weak sidewalls of the drawn and ironed aluminum container, the container employs the internal pressure of the carbonated beer or soft drink as a strengthening element. More recently, however, with the development of liquid nitrogen injection into filled containers, it has become feasible to package noncarbonated beverages, such as wines, juices, water and the like in aluminum cans. Of course, it is also known to package beverages, both carbonated and noncarbonated, in steel cans. In all such cases, the filled and sealed container includes a gaseous headspace above the product.
Unlike beer and soft drinks, which are packaged at or below room temperature, many of the noncarbonated beverages, especially fruit drinks, are packaged hot. After packaging, it is important to quickly cool the container and product, to avoid deterioration of the product.
Several apparatus have been disclosed in the past for can cooling. Thus, for example, U.S. Pat. Nos. 2,477,992; 2,597,223; 2,677,248 and 3,283,523 all disclose apparatus in which cans are conveyed along a conveying surface and sprayed with water to cool the cans. The cans are rotated along their path in order to aid the cooling process.
Unfortunately, it has been found that spray cooling does not provide sufficient contact between the water and the container for efficient cooling, resulting in the need for excess water usage and/or excess conveyor length. Further, since the containers were rolled along the conveying surface, damage to the containers and/or their graphics remained a problem.
In U.S. Pat. No. 3,092,125, a can cooler is described which employed countercurrent flow of the containers and a water trough along a portion of the conveying path and which employed water spray during another portion of the conveying path. Further, the cans were rocked in an arc in order to improve cooling of the contents. While improvement over the full water spray systems was accomplished, there remained the need for elimination of excess water consumption from water sprays, as well as the need for further improvements in container cooling.
Further, in all of the prior known apparatus for can cooling, movement of the container occurs merely by mechanical means, without using the physics of the container itself to aid in its cooling.
It is thus a primary objective of the present invention to employ the container as a major contribution to its own cooling.